The days of sloughing our faces with apricot kernels in the name of exfoliation are for the most part, over. And thank goodness- no one on this earth needs to effectively take a brillo pad to their delicate facial skin. Feet yes, face no. Exfoliation has moved on from rough physical scrubs to chemical exfoliants that work to whisk away dead skin cells while also smoothing skin texture, giving pores a clear out and boosting skin hydration. Not an abrasive shell or scratchy bead in sight.
The thing is, acids by their very nature can be a bit scary. There’s something about applying an acid solution to one’s visage and just...leaving it there...that can be a bit daunting. A bit like waiting for a test tube reaction during GCSE chemistry and hoping you followed the instructions correctly, acid toning can quite literally be an exact science, with dosage, frequency of use and exact chemical composition all key to achieving a smooth result. Overdo the powerful alpha hydroxy acid (AHA) peels and you’re likely to end up with stingy, red and raw skin, and if you’re skin’s on the sensitive you may not be able to tolerate AHAs at all. Betahydroxyacids (BHAs) tend to be milder, but if you suffer with acute sensitivity , rosacea , eczema , very dry or flaky skin, an even more agreeable acid is rising to exfoliation eminence: polyhydroxy acids, termed PHAs. Here’s your PHA ‘how to’.
What are PHAs and how do they differ from AHAs and BHAs?
Aesthetic facialist Kate Kerr explains what sets PHAs apart:
“Polyhydroxy acids, of which lactobionic acid and gluconolactone are examples, are larger molecules than AHAs, and as a result they have a lesser ability to penetrate into the skin. This isn’t a bad thing- it means that PHAs offer slower penetration and a much more gentle exfoliating action.”
So while AHAs are smaller molecules and penetrate skin at speed, which is good news for quick results but can prove problematic for reactive skin, PHAs dissolve the protein bonds that “glue” dead skin to our face and body (delicious) at a slower rate, yet still give skin cell turnover a chivvy on while improving skin’s surface texture. As for BHAs, AlumierMD education specialist Victoria Hiscock highlights that they have specialist skills that are most suited to acne and blackhead prone skin :
“BHAs are drawn to oil in the skin and so penetrate the pores rather than necessarily working on the skin’s surface itself.”
As such, each acid has its place depending on your particular skin concern, but we’ll dig a bit deeper into the PHA profile for starters…
Why should I add PHAs to my skincare routine?
Get ready to throw a PHA party. They don’t just clean up those rogue dead skin cells according to Kate:
“PHAs are humectants, which means they have the ability to attract moisture to the skin, improving hydration. They also have anti-inflammatory and antioxidant benefits that also contribute to making them them a more suitable chemical exfoliant for sensitive skin.
“What’s more, when used regularly they can have the ability to strengthen barrier function, making the skin stronger and more resilient over time and giving you more of that sought-after glow.”
If you still feel nervy about inviting PHAs in, Daniel Issacs, Head of Formulation and Development at Medik8 , has a few soothing words on how they work, and who they work for:
“PHAs work exclusively on the skin’s surface without disturbing the delicate layers that lie beneath- this ensures optimum skin renewal with minimal irritation. As such, even very sensitive skin types can harness the resurfacing powers of PHAs. In clinical studies, they have been proven to be compatible with dry, itchy skin conditions such as eczema and atopic rosacea”
PHAs are starting to look like the mellow, chilled out acid option, but that could lead to accusations of laziness...
Can PHAs actually address the kind of skin issues that other acids tackle?
If you’re assuming that PHAs’ ‘gently, gently’ approach makes them less powerful for stubborn skin concerns such as pigmentation , Daniel puts that one to bed in the case of one particular PHA:
“Gluconolactone is a PHA that occurs naturally in human cells, thus it is well-received when applied to the skin. It is essentially oxidised glucose (a natural sugar that serves as the body’s primary source of energy). It is especially useful for those with pigmentation irregularities as it triggers cellular regeneration. This prompts the body to renew skin cells more frequently, pushing melanin-rich cells to the surface in much shorter time frame. At the same time, gluconolactone’s exfoliating properties accelerate the skin-shedding process, ensuring darkened cells are efficiently dissolved to reveal a brighter, clearer complexion.”
How should I use PHAs in my regime?
PHAs take various shapes, but Kate advises considering strength and how often you’re using them as a benchmark:
“PHAs can be incorporated effectively in a range of different products, from toners to serums and masks. I would recommend assessing how you plan on using the product and the strength of the PHA before committing to one product type. For example, when using a toner everyday, a lesser strength PHA is to be expected, when compared to a mask with a higher concentration of PHA that you’ll use less often.”
As a general rule, unlike more potent AHAs such as glycolic acid that can trigger barrier damage and inflammation when overused, PHAs are gentle enough to be used everyday by most skin types. Go for a targeted serum for optimum absorption.
Can I combine PHAs with other skincare products?
Roger that. Victoria emphasises that mixing PHAs with other beneficial skincare ingredients can lead to quite the compelling skincare cocktail:
“Combining PHAs with AHAs can lead to extraordinary outcomes for patients when it comes to brightening. If you’re looking for more aggressive results, combining PHAs with up to 1% vitamin A can reap exceptional rewards in terms of reducing pigmentation and rejuvenating skin.”
Obviously if you do have very sensitive skin approach stronger skin concoctions with caution. The more tame effect of PHAs also means that they can be used alongside clinical and professional treatments such as microdermabrasion and laser treatments, unlike more aggro AHAs, but always check with your dermatologist or aesthetician before proceeding to board the PHA train, just in case.
Should anyone avoid PHAs?
The general consensus is no, although Kate highlights that other acids might serve you better, depending on your skin priorities:
“Those suffering with acne should avoid in favour of more effective treatments such as salicylic acid (BHAs) that can penetrate further into the skin.”
Also, if you’re anointing yourself with a PHA + retinol blend or similar, Victoria underlines that the usual safeguarding rules apply:
“Due to the tender nature of PHAs, they can generally be used without caution. They can even be used daily when formulated with retinol or lactic acid, for example, although this does depend on your individual tolerance, and bear in mind to limit use to evenings only to avoid post-exfoliation photosensitivity.”
Also, wear sunscreen, but you knew that.
Why all of this PHA chat all of a sudden?
PHAs haven’t sprung from nowhere: they were discovered by two doctors (Dr Van Scott and Dr Yu.) in the 1970s, but are finally out of patent, which was formerly held by skincare brand Neostrata . Patenting laws previously meant that it was very costly for other companies to include PHAs in their formulas, but now many are going to town on this particularly temperate exfoliant. Neostrata’s PHA offering remains among the best for obvious reasons, but there are a number of other PHA powerhouses to look out. Here’s some I PHApared earlier. Sorry.